The present invention is directed to a bituminous emulsion roof resaturant for application to weathered built-up roof systems.
In one typical roofing system for office and industrial buildings the roofing is a multi-component system that is applied directly to the roof deck, the roof deck normally consisting of a corrugated steel decking supported on roof trusses. The multi-component system usually includes one or more layers of an insulation material (such as glass fiber insulation board or a rigid foam insulation board) that is adhered to the roof deck. One or more asphalt- or tar-impregnated felt layers then are adhered on top of the insulation material. A sealant coating of an asphalt or tar is applied over the impregnated felt layers. A layer of gravel then is spread over the coating of asphalt or tar.
After a period of aging and exposure to the elements, the sealant coating becomes eroded, checked and cracked. The impregnated felt layers during this same period lose their flexibility and are susceptible to being rented when the roof system expands and contracts during normal changes in ambient temperature. The cracking and checking of the sealant coating and the rending of the impregnated felt layers destroy the watertight integrity of the roofing system allowing water to permeate the insulation layers of the roof structure and impede their insulating function. Various attempts have been made to make the roof system watertight once again, but they have not been entirely satisfactory.
One approach to providing a solution to this problem involves merely applying an additional sealant coating (after removal of loose gravel) of asphalt or tar over the old checked and cracked sealant coating. While such new sealant coating provides a temporary repair, the movement of the rented relatively still impregnated felt layers during expansion and contraction of the roofing system during temperature fluctuation once again causes cracks to reoccur in the sealant coating resulting in the destruction once more of the watertight integrity of the roofing system.
In another attempt to provide a solution to the problem, a glass fiber fabric layer is applied over the weathered surface of the roofing system (after removal of loose gravel) and one or more coats of "cutback" bitumen or a bitumen emulsion are coated over the glass fiber fabric to adhere the fabric to the weathered surface and to impregnate and seal the glass fiber fabric. However, the glass fiber fabric, while it bridges over the tears in the impregnated felt layers, does not follow the contour of the felt layer surface very closely nor fit into the cracks and crevices that are present in the weathered sealant coat. As a result, tiny voids and pinholes form as the roofing structure expands and contracts and the watertight integrity of the roofing system once more is breached.